太湖流域某净水厂嗅味物质变化特征研究

为了探讨净水厂中嗅味物质的浓度变化规律与各级处理单元之间的关系,以期为净水厂更加高效地去除水中的嗅味物质提供依据,采用固相微萃取—气质联用技术对太湖流域某净水厂中的2-甲基异莰醇(2-methylisobornel,2-MIB)、土臭素(Geosmin,GSM)、β-紫罗兰酮(β-Ionone,p-Ion)和β环柠檬醛(pCyclocitrial,p-Cyc)4种特征嗅味物质进行检测,并分析比较了净水厂各级处理单元对嗅味物质的去除效果.结果表明:β-Cyc的平均浓度最高,为5.83 μg/L,其次为β-Ion,平均浓度达到41.36 ng/L,2-MIB和GSM的平均浓度相对较低,分别为4.02 ng/L、l.13 ng/L;净水厂处理工艺对2-MIB、β-Cyc、β-Ion和GSM的去除率分别为99.93％、93.73％、64.09％和0;净水厂的处理工艺对嗅味物质具有一定的去除效果,嗅味物质浓度沿着水处理工艺流程呈下降趋势,嗅味物质的去除主要发生在深度处理阶段.     

平原水库水质变化及产生异嗅味原因分析

通过在平原水库2个出水口不同深度上取水样进行试验,分别对进出水CODMn、氨氮、硝酸盐氮、亚硝酸盐氮浓度变化情况,以及原水总磷浓度变化情况进行了检测和分析。根据对溶解氧、嗅阈值、MIB浓度与藻类总数之间关系,以及滤后出水余氯的分析,判断得出平原水库产生异嗅味原因是水体中氮、磷等营养物质浓度过高;低温藻类在水体中产生的分泌物为典型的异嗅味物质,且在封冻条件下难以挥发;水中氨氮浓度过高,氯消毒过程中产生的二氯胺、三氯胺等化合性氯加剧了处理水的异嗅味。     

Fenton高级氧化技术去除水中有机污染物2-MIB的影响因素研究

针对目前比较关注的致嗅物质污染问题,选用Fenton高级氧化技术研究了其对水中致嗅物质2-甲基异莰醇（2-MIB）的去除,探讨了Fenton反应对水中致嗅物质的去除效能及H2O2/Fenton摩尔比、Fe2＋浓度、反应时间和溶液pH值各因素对氧化反应的影响。提出了Fenton氧化反应去除2-MIB的最佳反应条件。实验结果表明：Fenton高级氧化能有效去除水中的2-MIB。在H2O2/Fenton摩尔比为3.0、Fe2＋浓度10 mg/L、反应时间10 min和溶液pH值为3.0时,去除效率达到97.9%。Fenton氧化反应的操作条件（浓度、pH值等）比较容易实现,因此Fenton氧化技术在实际污染处理中有很大的应用前景。     

东太湖水体中嗅味物质分布及网围养殖对其影响

东太湖是太湖流域重要的水源地,苏州市吴江区取水口位于其中,水体中出现异嗅味。为了解东太湖水体中嗅味物质的空间分布及甄别围网养殖可能对其的影响,在东太湖的不同区域设置监测点位,利用GC-MS对水体中的嗅味物质进行监测。结果表明:1)水体中嗅味物质2-甲基异莰醇(MIB)和土嗅素(Geosmin)的浓度分布具有显著的空间异质性,其浓度随距养殖区域距离的增加而递减;2)水体中嗅味物质2-MIB和Geosmin的浓度与温度显著正相关,当温度为最高时,其最大浓度分别达到1121.99 ng/L和34.29 ng/L;3)水温和硝酸盐氮浓度对2-MIB浓度有极显著影响(P 0.01),水温越高,硝酸盐氮浓度越高,2-MIB浓度越高,总磷浓度和硝酸盐氮浓度对土嗅素浓度有显著影响(P 0.05)。网围养殖可能是水体中嗅味物质的一个重要来源,在东太湖及其它水源地治理中应引起高度重视。     

深圳市某水库嗅味物质时空分布及去除研究

考察了深圳市内某水库嗅味物质的时空分布及给水厂常用处理工艺对嗅味物质的去除效果,并提出了嗅味物质强化去除的手段。结果表明:该水库中主要致嗅物质为2-甲基异茨醇(2-MIB),在采集的水样中2-MIB超标率高达70.4%。水库中两种嗅味物质[2-MIB和土溴素(GSM)]浓度随季节变化规律明显,夏秋季节显著高于春冬季节。在水平方向上,2-MIB和GSM浓度均在库中C点最低;在垂直方向上,两种嗅味物质浓度随水深变化不显著。当前给水厂混凝沉淀和过滤工艺对嗅味物质去除效果较差,粉末活性炭吸附可有效去除2-MIB和GSM。当2-MIB和GSM初始浓度均为100 ng/L,活性炭投量为20 mg/L时,经90 min吸附二者去除率均超过97%,且活性炭对二者的吸附过程符合Freundlich模型。     

珠海市饮用水水源藻类问题分析与解决方案

为探究珠海市多水源供水体系下存在的水源水质问题,特别是藻类问题,采用单因子分析法评价2016—2019年珠海市4座典型水库的数项水质指标,并采用统计学方法分析水库水中藻类的时空分布特征;采用双变量分析及逐步回归分析的方法研究10项水质指标与藻密度间的相关性。基于对水质数据的分析发现:珠海市水源水存在较为突出的高藻密度及高嗅味问题,其中,藻密度从春季开始普遍出现上升,而嗅味物质的质量浓度则秋冬季达到峰值,二者存在较为明显的季节性变化。回归分析的结果表明:影响水库藻密度的主要因素有总氮、高锰酸盐指数和五日生化需氧量;影响嗅味物质产生的主要因素有氨氮、高锰酸盐指数和浊度;控制水库水体的氨氮和有机物含量可以有效减少藻类数量,改善嗅味物质的产生。建立的拟合优度较高的回归模型可以用于初步预测水库水质。通过点、面源污染的控制,调节水库水体流态,结合臭氧活性炭、紫外高级氧化等深度处理技术的应用,可以有效解决珠海市水源水存在的高藻及嗅味问题。     

基于电子鼻技术检测水体异嗅等级的方法研究

为了快速准确地判别异嗅强度等级,将电子鼻技术应用于饮用水异嗅异味检测中,提出了电子鼻检测的优化方法并通过电子鼻信号建立了确定嗅味等级的数学模型.试验结果表明待测水样为200 mL、水浴温度65℃,加热时间10 min,进样方式顶空进样,可大幅度提高电子鼻传感器的检测灵敏度,使得电子鼻检出限与饮用水中低浓度嗅味物质相匹配.将优化方法用于实际水体的嗅味检测,结合嗅味层次分析(FPA),通过多元线性回归PLS方法,建立电子鼻响应值和饮用水异嗅等级的数学模型,R2达0.986.     

东太湖水源水致嗅氨基酸以及常规与O3-PAC工艺的处理效能

已有研究表明,某些氨基酸在氯化消毒过程中能形成有嗅味的醛类、腈类和N-氯代醛亚胺。在评价了天然水体中可能存在的20种氨基酸的产嗅强度的基础上,考察了东太湖各季节氨基酸种类、浓度变化,确定了东太湖水源优势氨基酸以及致嗅氨基酸的种类,研究了常规工艺和臭氧-活性炭工艺对东太湖水源水中氨基酸的去除规律。结果表明,东太湖水源水中的氨基酸种类和含量季节性差异较大,总氨基酸浓度及致嗅氨基酸的峰值均出现在秋季;常规工艺中,混凝沉淀对氨基酸去除起主要作用,秋季去除率为30.3%,砂滤出水氨基酸浓度有时会升高。臭氧-活性炭(O_3-PAC)工艺对致嗅氨基酸的去除率为14.6%～55.8%,很不稳定,主要因为影响O_3-PAC去除氨基酸的因素较多,故生产中需要对O_3-PAC运行工况进行合理优化和严格管理。     

高锰酸钾复合药剂对水中藻类和嗅味去除效果生产性试验研究

本文以生产试验结果为依据，较为系统地考察了高锰酸钾复合药剂（ＣＰ）预处理工艺去除水中藻类和嗅味的效果，并与聚合氯化铝（ＰＡＣ）混凝效果做了对比研究。试验表明，高锰酸钾复合药剂预处理工艺在去除藻类和嗅味方面具有较好的效果。     

水源水质标准中嗅味标准的研究

在我国现有的《生活饮用水水源水质标准》(CJ3020-93)标准中并未对嗅味做定性和定量的规定。嗅味层次分析方法能够对水样中的嗅味种类以及嗅味强度做出定性和定量化的判断,通过嗅味层次分析方法以及SPME-GC/MS化学分析的结果,给出了饮用水嗅味的推荐值。按不同水源地类型对二甲基异莰醇(2-MIB)的标准进行了研究,综合考虑感官分析和化学分析结果,水厂可处理程度以及消费者可接受情况,给出2-MIB标准的推荐值,一级、二级水源地的标准推荐值为10 ng/L,三级水源地的标准推荐值为50 ng/L。二甲基异莰醇(2-MIB)嗅味标准推荐值的给出在一定程度上对水源地的划分又提供了一个参考依据,开辟了水质感官分析的新思路,为我国城市水源中2-MIB含量的划分提供了参考。     

Treatment of taste and odor material by oxidation and adsorption.

Massive blooms of blue-green algae in reservoirs produce the musty-earthy taste and odor, which are caused by compounds such as 2-MIB and geosmin. 2-MIB and geosmin are rarely removed by conventional water treatment. Their presence in the drinking water, even at low levels (ng/L), can be detected and it creates consumer complaints. So those concentrations have to be controlled as low as possible in the drinking water. The removals by oxidation (O3, Cl2, ClO2) and adsorption (PAC, filter/adsorber) were studied at laboratory and pilot plant (50 m3/d) to select suitable 2-MIB and geosmin treatment processes. The following conclusions were derived from the study. Both of the threshold odor levels for 2-MIB and geosmin appeared to be 30 ng/L as a consequence of a lab test. For any given PAC dosage in a jar-test, removal efficiencies of 2-MIB and geosmin were increased in proportion to PAC dosage and were independent of their initial concentration in raw water for the tested PAC dosages. In comparison of geosmin with 2-MIB, the adsorption efficiency of geosmin by PAC was superior to that of 2-MIB. The required PAC dosages to control below the threshold odor level were 30 mg/L for geosmin and 50 mg/L for 2-MIB at 100 ng/L of initial concentration. Removal efficiencies of odor materials by Cl2, ClO2, and O3 were very weak under the limited dosage (1.5 mg/L), however increased ozone dosage (3.8 mg O3/L) showed high removal efficiency (84.8% for 2-MIB) at contact time 6.4 minutes. According to the initial concentrations of 2-MIB and geosmin, their removal efficiencies by filter/adsorber differed from 25.7% to 88.4%. For all those, however, remaining concentrations of target materials in finished waters were maintained below 30 ng/L. The longer run-time given for the filter/adsorber, the higher the effluent concentration generated. So it is necessary that the run-time of the filter/adsorber be decreased, when 2-MIB or geosmin occurs in raw water.     

Efficiency of membrane processes for taste and odor removal.

The occurrence of tastes and odors (T&O) in drinking water is considered as one of the main problems by the drinking water companies. Thus, several treatment processes were developed over the years to control T&O including air stripping, activated carbon and oxidation using ozone. However, little information is available in the literature on the use of membranes for T&O removal. Therefore, the objectives of this paper are to present potential of membrane processes for removal of taste and odor causing compounds. Several membranes were tested including ultrafiltration (UF), UF combined with powdered activated carbon (PAC), nanofiltration (NF) and low pressure reverse osmosis (LP RO) membranes. The results of this study indicate that the combination of UF with PAC is effective for T&O control whereas the benefit of NF and LP RO remains unclear for T&O control.     

The effect of applying a pipe-joint lubricant to connect ductile iron pipe on off-flavors in drinking water distribution systems.

This study was used to help define the contribution to taste and odor problems caused by the application of a pipe-joint lubricant to connect ductile iron pipe in drinking water distribution systems. Tyton Joint Lubricant (TJL) was studied. The lubricant produced odors that are continually oxidized by chlorine or oxygen. The mechanism of oxidative rancidity, one of the major causes of food spoilage is the apparent mechanism of oxidation. The odors produced by the lubricant were characterized by a Flavor Profile Analysis (FPA) panel as well as GC/MS and Sensory GC analysis. The most common odors perceived in the TJL water samples for the first six days were waxy/oily and soapy odors with a rancid oil, odor note. The waxy/oily and soapy odors decreased with time in the chlorine medium as the rancid oily odor note increased. Numerous aldehydes, ketones, alcohols and borneol compounds, produced from the lubricants, were tentatively identified and linked to the odors perceived by the FPA panel.     

饮用水中臭和味问题分析及去除方法

系统阐述了近年来国内外饮用水臭味问题的相关研究。首先,详细阐明了饮用水中臭和味的重要来源;其次,从感官、仪器、综合分析法等三个方面,简述了臭味物质的定性和定量检测技术,指出了制定滤后水、出厂水、管网水及二次供水中致臭物质量化标准限值的必要性和紧迫性;最后,根据臭和味的来源,提出了相应的解决方法与措施。     

Understanding odorants associated with compost, biomass facilities, and the land application of biosolids.

Odorous water and air can result from compost, biomass facilities and land application of biosolids. Common odorous compounds from these biodegradation systems include alcohols, aldehydes, fatty acids, solvents and various sulfur and nitrogen compounds. Each odorant possesses a unique individual odor signature i.e. odor character or quality, odor threshold concentration and chemical concentration. This paper develops an initial understanding of how the volatile odorous chemicals and their relative concentrations produced are related to the total odor quality from the process by their odor threshold concentrations. The compost process is used as an example. It was estimated, that on day 1 and 7, the primary fatty acids controlling the fermented and rotten odors were butyric acid and valeric acids, individually, unpleasant and rancid odors, respectively, although acetic acid had the highest fatty acid concentration on both days. In the same way, aldehydes and ketones controlled the disappearance of the sweet odor from day 1 to 7.     

Removal of geosmin and 2-methylisoborneol by biological filtration.

The quality of drinking water is sometimes diminished by the presence of certain compounds that can impart particular tastes or odours. One of the most common and problematic types of taste and odour is the earthy/musty odour produced by geosmin (trans-1, 10-dimethyl-trans-9-decalol) and MIB (2-methylisoborneol). Taste and odour treatment processes including powdered activated carbon, and oxidation using chlorine, chloramines, potassium permanganate, and sometimes even ozone are largely ineffective for reducing these compounds to below their odour threshold concentration levels. Ozonation followed by biological filtration, however, has the potential to provide effective treatment. Ozone provides partial removal of geosmin and MIB but also creates other compounds more amenable to biodegradation and potentially undesirable biological instability. Subsequent biofiltration can remove residual geosmin and MIB in addition to removing these other biodegradable compounds. Bench scale experiments were conducted using two parallel filter columns containing fresh and exhausted granular activated carbon (GAC) media and sand. Source water consisted of dechlorinated tap water to which geosmin and MIB were added, as well as, a cocktail of easily biodegradable organic matter (i.e. typical ozonation by-products) in order to simulate water that had been subjected to ozonation prior to filtration. Using fresh GAC, total removals of geosmin ranged from 76 to 100% and total MIB removals ranged from 47% to 100%. The exhausted GAC initially removed less geosmin and MIB but removals increased over time. Overall the results of these experiments are encouraging for the use of biofiltration following ozonation as a means of geosmin and MIB removal. These results provide important information with respect to the role biofilters play during their startup phase in the reduction of these particular compounds. In addition, the results demonstrate the potential biofilters have in responding to transient geosmin and MIB episodes.     

O_3和O_3/H_2O_2氧化对饮用水中痕量臭味物质的处理效果研究

研究了O3、O3/H2O2深度氧化法对饮用水中的Geosmin、MIB、IBMP、IPMP及TCA等痕量异味物质的去除效能。当O3投加量为4.66mg/L时,对痕量异味物质的去除率按IBMP、TCA、Geosmin、IPMP和MIB的排列,其中对Geosmin的绝对去除量最大,达到了140ng/L。投加O30.43mg/L和H2O210mg/L氧化去除5种痕量异味物质,对IBMP和TCA去除率分别达到75%和67.2%,去除效率较高;但在O3及O3/H2O2这样的投加量下,痕量异味物质尚不能达到标准中对嗅阈值的要求,还需配合后续处理工艺。     

Physical Processes Controlling Taste and Odor Episodes in Lake Ontario Drinking Water

Circulation and thermal structure of the coastal waters were studied as a part of an interdisciplinary program to investigate the taste and odor problem in drinking water along the north and western shores of Lake Ontario. The currents and temperature variations were found to be strongly linked to winds, with winds from the west causing upwelling and eastward flowing currents, and winds from the east inducing downwelling and warm westward flowing currents. The downwelling along the north shore during late August and early September of 2000 was associated with a pulse in concentration of the taste and odor causing compound geosmin. This study indicates that during this episode the onshore directed mean currents and cross-shore fluxes in the surface layer transported geosmin to the coastal waters of the north shore.     

Sensory evaluation of the odors produced during bromophenol formation using a multi-level statistical model.

In response to reports of medicinal taste and odor problems in suburban Paris, a lab scale study was conducted to investigate the contribution of different water quality parameters--pH, phenol, bromide, chlorine, temperature and dissolved oxygen levels--on bromophenol medicinal odor formation using the Flavor Profile Analysis (FPA) method. A study of six parameters at 2 levels (64 experiments) analyzed by the FPA method suggests that chlorine at high concentration is more important as a controlling agent than phenol under similar conditions and the ratio of HOBr:Phenol and the time for reaction will control subsequent brominated products of reaction. Results from a three-level statistical model indicate that high pH was associated with lower odor intensities, whereas high levels of chlorine, phenol and temperature were associated with high odor intensities. Potential worst case scenarios of water quality conditions were determined for evaluation by chemical identification and kinetics.